The research objectives have included studying several aspects of lymphocyte biology and transplantation immunology. Transplantation procedures are also being employed to elucidate the mode of action of some coat-color determinants in mice. Specifically the projects conducted to date have been concerned with (1) analyzing the cellular basis of tolerance in neonatally induced mouse chimeras; (2) determining the influence of rat cells of various Ag-B genotypes to induce lethal graft-versus-host reactions in mice (including rat donors congenic with respect to Ag-B and mouse recipients congenic with respect to H-2); (3) analyzing in detail the behavior of the male specific antigen in rats and (4) elucidating, with transplantation procedures, the mode of action of two loci (the "agouti locus" and the "extension locus") concerned with the production of yellow hair pigment and of a locus (the "steel locus") whose effects include the elimination of melanocytes, anemia and a deficiency of germ cells, in mice. BIBLIOGRAPHIC REFERENCES: Silvers, W.K., Elkins, W.L. and Quimby, F.W., 1975. Cellular basis of tolerance in neonatally induced mouse chimeras. J. Exp. Med. 142: 1312-1315.